THE WARM, HARD FACTS.

Byline: Susan Palmer The Register-Guard

You can understand why Hollywood cooked up a movie on global climate change. Lush forests morphing into ice sheets. Brushland becoming desert. Thousands of species dying.

From an apocalyptic cinematic point of view, what's not to like?

But the scientists who study the planetary vagaries of past and present weather patterns just roll their eyes and shake their heads over "The Day After Tomorrow," the disaster movie opening Friday nationwide (with a preview Thursday night in Eugene).

Even the most abrupt climate changes take years to manifest. Witnessing it unfolding would be about as exciting as, well, watching ice melt.

So it's not surprising that director Roland Emmerich - the guy who brought us massive earthly destruction via aliens in "Independence Day" - would take a little dramatic license in his latest effort to scare us silly. OK, make that a lot of dramatic license.

In "The Day After Tomorrow," the polar ice caps melt suddenly, swamping Manhattan in a colossal tidal wave. Three days later, the onset of an instant ice age flash-freezes the city. Various other weather monstrosities rain havoc on several of the planet's other major metropolises.

So, now for the reality check: University of Oregon paleoclimatologist Patrick Bartlein agreed to set the record straight on some of the film's more outlandish scenes - shown for weeks in trailers across the country.

Despite the movie's wild embellishment, Bartlein figures that the film may actually do some good in spurring people to think about their role in the current increase in planetary temperatures - by almost 2 degrees in the past 100 years. "We know it's a story and the science is pretty far-fetched, but if it gets people interested in abrupt climate change, that's good," he said.

Here's his analysis:

Trailer: It begins with white words on a black screen "Ten thousand years ago, one storm changed the face of the planet."

Reality: Nope. Nature's planetwide temperature changes take years to accomplish, not hours.

Trailer: A tidal wave pounds Manhattan, hurling buses down city streets, engulfing cars and people, eventually leaving the Statue of Liberty up to her armpits in water.

Reality: Not exactly. While winds do push water around and while the circulation of ocean currents tends to keep water piled up in the central Atlantic, a sudden change in currents would more likely cause the water to spread out, with increases of a few inches, not massive tsunamis.

Trailer: Following the tidal wave, New York sinks into a fast freeze. Lady Liberty along with all of Manhattan's skyscrapers are suddenly encased in ice.

Reality: Forget about it. Even if the North Atlantic cooled by 4 to 6 degrees, Bartlein said, it wouldn't be cold enough to glaciate North America or Europe.

Trailer: The same North Atlantic gulf stream cooling that hammers Manhattan spawns tornadoes in Los Angeles and hail the size of golf balls in Tokyo.

Reality: Borderline. Changes in the North Atlantic gulf stream - which Bartlein likes to call the global conveyor belt - will result in weather changes all over the world. Here in the Willamette Valley, we'd likely see weather patterns similar to those just north of us in Western Washington or British Columbia. But tornadoes result from a very specific set of local conditions, warm moist air rising to bump into colder dry air. The sudden influx of cold water from melting glaciers wouldn't be more or less likely to create those conditions, he said.

So what do the best computer models of the future tell us? Bartlein, who is part of the UO Environmental Change Research Group and who teaches courses on environmental change, expects a slowdown in the gulf stream rather than a complete halt.

"It's nowhere near as dramatic as the movie portrays it," he said.

More realistic scenarios can be found at the movie's official Web site, Bartlein pointed out. There, filmmakers describe the more likely effects of global warming in North America.

Skiers, for instance, can say goodbye to pristine powder in the Colorado Rockies. Hikers can say hello to mosquitoes carrying malaria and dengue fever. Animal lovers can kiss some furry and feathered buddies goodbye. The planet could lose thousands of species.

All are possible if the planet continues its slow-motion heat wave, Bartlein said. When and how bad and for how long are all questions still up for grabs.

"What I'm saying is, we don't know what's coming," he said. "It's almost a shakier position to be in than if we knew for sure. Climatology has lost ground in understanding how the world works, not because we haven't been doing anything, but because it's gotten more complicated."

IN A NUTSHELL

Global climate change: Records show that the planet's weather changes over hundreds of thousands of years, ushering in ice ages before slowly swinging in the opposite direction. Most scientists believe that our reliance on fossil fuels is responsible for a current abrupt warming trend. The fuels that power vehicles and industries and that warm or cool homes kick more carbon dioxide into the air than nature alone does. That increases the greenhouse gases that keep the Earth warm. The more gases, the warmer the planet and the greater the global impact.

CAPTION(S):

A tsunami slams into New York City in a scene from "The Day After Tomorrow."